# What is hormone therapy for cancer? Source: https://oncologyistanbul.com/answers/what-is-hormone-therapy-for-cancer Last updated: 2026-07-12 According to the U.S. National Cancer Institute (NCI), hormone therapy is a cancer treatment that slows or stops the growth of cancer that uses hormones to grow. NCI explains it works in two main ways: treatments that block the body's ability to produce hormones, and treatments that interfere with how hormones behave in the body. It is used to treat prostate and breast cancers that use hormones to grow. NCI notes that, combined with other treatments, hormone therapy may make a tumor smaller before surgery or radiation therapy (neoadjuvant therapy), lower the risk that cancer will come back after the main treatment (adjuvant therapy), or help destroy cancer cells that have returned or spread. Reported side effects can include hot flashes, fatigue, and changes in sexual function. This is general information, not personal medical advice; discuss your situation with your own care team. ## Verify at - [Hormone Therapy to Treat Cancer](https://www.cancer.gov/about-cancer/treatment/types/hormone-therapy) — National Cancer Institute (NCI) (checked 2026-07-12) Related: [Neoadjuvant vs adjuvant therapy](https://oncologyistanbul.com/answers/neoadjuvant-vs-adjuvant-therapy)